Abiogenese

Abiogenesis is the natural process by which living organisms arise from non-living matter. It is distinct from biogenesis, which holds that life comes only from existing life, and from spontaneous generation, a discredited idea that life can arise unexpectedly under certain conditions.

Historically, scientists debated whether life required a vital force or could emerge from chemistry. The field gained momentum in the mid-20th century when experiments showed that organic molecules can form under plausible prebiotic conditions. The 1953 Miller-Urey experiment demonstrated amino acids produced from simple inorganic precursors in a reducing atmosphere, supporting chemical plausibility for abiogenesis.

Current accounts describe a sequence of stages: prebiotic chemistry producing organic monomers; polymerization to macromolecules; concentration within compartments; and the emergence of self-replicating information carriers, such as RNA, within membranes. These steps could lead to primitive metabolic networks and protocells that eventually evolve into true cells.

Possible environments include shallow pools and hydrothermal vent systems where minerals, gradients, and cycles of water and nutrients could drive reactions. Estimates place the origin of life on Earth roughly between 4 and 3.5 billion years ago, with the last universal common ancestor (LUCA) being the earliest shared lineage rather than the first organism.

Abiogenesis remains an active research area with many unresolved questions. Researchers pursue experimental chemistry, geology, and computer modeling to test proposed pathways and to assess how likely life is to arise under various planetary conditions.